The invention relates generally to the field of drive assemblies for dual coacting rollers, such as found in roll forming machines, sheet feeding machines, roll milling machines or the like, where the machinery includes a pair of parallel rollers mounted onto roller shafts contained in a frame or support, with the rollers being rotated in opposite directions such that sheet material or other objects are pulled between and passed through the rollers. More particularly, the invention relates to such drive assemblies for dual coacting rollers in which the separation distance or gap between the two rollers is adjustable.
There are various types of drive assemblies for dual coacting rollers, wherein the rotational power is transferred to the rollers by single or multiple chains, gearing, belts or the like. A typical machine utilizes a complicated gear box, sprockets or toothed gears mounted onto to the central shafts of the rollers, with chains or timing belts running from a motor to the sprockets or gears. Examples of these types of machines can be seen in U.S. Pat. No. 2,481,201 to Collier, U.S. Pat. No. 2,144,841 to Glaser, U.S. Pat. No. 3,208,677 to Hesse, U.S. Pat. No. 4,545,541 to Jensen, U.S. Pat. No. 4,621,966 to Luperti et al., U.S. Pat. No. 5,566,902 to Thom, Jr., U.S. Pat. No. 5,697,292 to Simmons, U.S. Pat. No. 5,697,880 to Auerbach, and U.S. Pat. No. 6,247,691 to Drago et al.
It is often necessary or at least desirable to adjust the separation distance or gap between the rollers, or to change the diameter of one of the rollers in order to adjust the reduction ratio. In the known systems such an adjustment or change is excessively complicated due to the need to readjust the tension on the chain or belt after the gap between the rollers has been widened or narrowed, or after one of the rollers has been switched for a roller of different size. This is especially true in machines that use a gear box.
It is an object of this invention to provide a drive assembly for dual coacting roller machines wherein the rollers are rotated in opposite directions such that sheet material or other objects are pulled between and passed through the rollers, wherein the separation-distance or gap between the two rollers is adjustable, and wherein the rotational power is transferred to the rollers through a combination of sprockets or toothed gears and timing belts or chains, such that the gap between the rollers can be easily adjusted without the need for a complicated re-tensioning of the drive belt or chain. It is a further object to provide such a drive assembly wherein the tension of the timing belt or chain is automatically and directly accomplished upon the repositioning of the roller. It is a further object to provide such a drive assembly wherein the motor or other power means for rotating the shafts can be disposed to either side of the roller pair. It is a further object to provide such a drive assembly where the rotational speed can be easily changed by substitution of sprockets or gears of differing diameters. These objects expressly set forth are supported in the following disclosure, and other objects not expressly set forth above will be apparent as well upon review of the following disclosure.
The invention is in general an improved drive assembly for dual coacting rollers, such as found in roll forming machines, sheet feeding machines, roll milling machines or the like, where the machinery includes a pair of parallel rollers mounted onto roller shafts contained in a frame or support, with the rollers being rotated in opposite directions such that sheet material or other objects are pulled between and passed through the rollers. The invention is particularly suited for such machinery where it is desirable or necessary to adjust the separation distance or gap between the two rollers, or to allow for a change of one roller to increase or decrease the roller diameter in order to adjust the reduction ratio. The drive assembly comprises four sprockets, pulleys or gears interconnected in serpentine fashion by a double-sided, toothed belt, often known as a twin timing or power belt, or by a chain or similar means. The sprockets comprise in combination a driven sprocket mounted on or connected to a first roller shaft, shown herein for illustrative purposes as the upper or outer roller shaft, the term outer typically signifying the roller disposed outermost from a table, floor or plate member of the machine, a drive sprocket mounted on or connected to a second roller shaft, shown herein as the lower or inner roller shaft, a paired idler sprocket in fixed spatial relation to the driven sprocket, shown herein as positioned toward the forward or ejection side of the assembly, and a tensioner idler sprocket, shown herein as positioned toward the rear or receiving side of the assembly, although such positions could be reversed. In one embodiment the paired idler sprocket and the tensioner idler sprocket are positioned generally adjacent, below or extended in the drive sprocket direction of the drive assembly, and in another embodiment of the invention are positioned generally adjacent, above or extended in the driven sprocket direction of the drive assembly. The drive sprocket is rotated by power means, such as for example an electric or hydraulic motor, such that rotation of the drive sprocket results in rotation of the remaining sprockets due to movement of the serpentine belt, and thus rotation of the shafts and rollers themselves.
The tensioner idler sprocket is preferably mounted on a fixed mounting bracket that is connected to the roller frame and retains the drive sprocket, with the tensioner idler sprocket being adjustable relative to the drive sprocket. As shown in a preferred embodiment herein, the tensioner idler sprocket is mounted within a generally vertical or slightly angled slot disposed on the lower portion of the fixed mounting bracket such that the vertical position of the tensioner idler sprocket can be altered relative to the drive sprocket. The fixed mounting bracket allows for movement of the tensioner idler sprocket for adjustment of the tension on the double-sided toothed belt or chain as needed. In an alternative embodiment, the tensioner idler sprocket is mounted onto an adjustable mounting bracket in combination with the driven sprocket, wherein the adjustable mounting bracket is movable relative to the roller frame or support and relative to the first roller and drive sprocket.
The driven sprocket and the paired idler sprocket are preferably mounted on an adjustable mounting bracket, preferably generally L-shaped as shown herein, with the driven sprocket and the paired idler sprocket being in fixed spatial relation to each other. The adjustable mounting bracket is movable relative to the roller frame or support and relative to the second roller and drive sprocket, such that the size of the gap between the two rollers can be adjusted by raising or lowering the first roller relative to the roller frame and the second roller. Such action results in the corresponding raising or lowering of the adjustable mounting bracket such that the spatial relationship of the driven sprocket and the paired idler sprocket remains unchanged, and therefore the proper rotation speed of the first roller is maintained. In similar manner, should it be desired to change the diameter of one or both rollers, the adjustable mounting bracket will insure that the proper relationship between the driven sprocket and the paired idler sprocket, and the proper rotation speed of the two rollers, is not changed. In an alternative embodiment, the paired idler sprocket is mounted onto a fixed mounting bracket in combination with the drive sprocket.
In alternative terms, the invention is a dual coacting roller machine, said roller machine having a first roller shaft and first roller and a second roller shaft and second roller mounted in parallel to define a gap between said first roller and said second roller, wherein said gap may be increased or decreased by repositioning said first roller shaft and said first roller relative to said second roller shaft and said second roller, said roller machine further comprising a drive assembly comprising:
a drive sprocket connected to said second roller shaft, such that rotation of said drive sprocket rotates said second roller shaft and said second roller;
power means for rotation of said drive sprocket;
a driven sprocket connected to said first roller shaft, such that rotation of said driven sprocket rotates said first roller shaft and said first roller;
a pair of idler sprockets;
a fixed mounting bracket connecting said drive sprocket to one of said pair of idler sprockets, and an adjustable mounting bracket connecting said driven sprocket to the other of said pair of idler sprockets in a fixed spatial relationship, such that repositioning of said driven sprocket results in corresponding repositioning of said other of said pair of idler sprockets;
a belt connecting said drive sprocket, said driven sprocket and said pair of idler sprockets, such that rotation of said drive sprocket results in rotation of said driven sprocket and said pair of idler sprockets;
whereby repositioning said first roller shaft relative to said second roller shaft results in corresponding movement of said adjustable mounting bracket relative to said fixed mounting bracket.
Additionally, the invention is a drive assembly for a dual coacting roller machine, said roller machine having a first roller shaft and a first roller and a second roller shaft and second roller mounted in parallel to define a gap between said first roller and said second roller, wherein said gap may be increased or decreased by repositioning said first roller shaft and said first roller relative to said second roller shaft and said second roller, and wherein said first roller shaft and said first roller relative rotate in a direction opposite to said second roller shaft and said second roller, said drive assembly comprising:
a drive sprocket connected to said second roller shaft;
a driven sprocket connected to said first roller shaft;
a pair of idler sprockets;
a belt connecting said drive sprocket, said driven sprocket and said pair of idler sprockets, such that rotation of said drive sprocket results in rotation of said driven sprocket and said pair of idler sprockets; and
a mounting bracket connecting said driven sprocket to one of said pair of idler sprockets in a fixed spatial relationship, such that repositioning of said driven sprocket relative to said drive sprocket results in corresponding repositioning of said one of said pair of idler sprockets.
Additionally, the invention is a dual coacting roller machine, said roller machine having a first roller shaft and a first roller and a second roller shaft and second roller mounted in parallel to define a gap between said first roller and said second roller, wherein said gap may be increased or decreased by repositioning said first roller shaft and said first roller relative to said second roller shaft and said second roller, and wherein said first roller shaft and said first roller relative rotate in a direction opposite to said second roller shaft and said second roller, and further comprising a drive assembly comprising:
a drive sprocket connected to said second roller shaft;
a driven sprocket connected to said first roller shaft;
a pair of idler sprockets;
a belt connecting said drive sprocket, said driven sprocket and said pair of idler sprockets, such that rotation of said drive sprocket results in rotation of said driven sprocket and said pair of idler sprockets;
power means to rotate said drive sprocket; and
a mounting bracket connecting said driven sprocket to one of said pair of idler sprockets in a fixed spatial relationship, such that repositioning of said driven sprocket relative to said drive sprocket results in corresponding repositioning of said one of said pair of idler sprockets.